The worldwide tablet market saw its first-ever year-over-year decline in the holiday quarter, but the biggest losses were seen by Amazon, which saw shipments of its budget-priced Kindle Fire series plummet 70 percent.

The latest quarterly estimates from IDC were published on Monday, revealing that tablet shipments in the December quarter were down 3.2 percent year over year.

Apple's numbers are already known —the company reported last week that sales of iPads were down 17.4 percent to 21.4 million units. But competitors such as Amazon, Samsung and the like do not report actual unit sales for their tablets, leaving industry watchers relying on estimates from firms like IDC.

IDC projects that Apple continued to hold the lion's share of the tablet market, shipping more than the next four closest competitors combined. Samsung was in second place with 11 million units, an 18.4 percent decline.

The only company among the top five to post gains was Lenovo, which grew its estimated shipments 9.1 percent to just 3.7 million units. It was followed by Asus, which saw its budget-priced tablets plummet 24.9 percent to 3 million units.

The worst, however, was seen by Amazon, whose Kindle Fire lineup saw a freefall of 69.9 percent in shipments, according to IDC. Amazon is estimated to have shipped just 1.7 million tablets in the quarter, good for a 2.3 percent market share.

Though the market is seeing sales decline, Apple Chief Executive Tim Cook has said he remains bullish on the future of tablets. In his company's quarterly earnings call last week, Cook said he sees great potential in the company's upcoming hardware pipeline.

Though he cautioned that he doesn't expect to see tablet sales improve in the short term, he said he sees the space as a long-term viable market. He noted that tablet users tend to be upgrading on a more PC-like timeframe, keeping their device for many years before replacing it, unlike the typical two-year upgrade cycle with smartphones.

One potential catalyst believed to be on the horizon for Apple is a rumored 12-inch tablet that has been dubbed the "iPad Pro." It's been suggested that Apple could use a larger and more powerful iPad model to cater to business customers.